There are a number of different type calendars out there. Part of it depends on the type of operating system you are running. MAC or Windows and the version. There is also just a basic online calendar, have you tried creating a Yahoo family group? or a place like http://www.calendars.net/ On a Mac system you can set it so you have a group calendar using ical. I am not sure of the best one for a windows system. I use an online calendar so I can update it from any computer.
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